This invention concerns a temperature control system for an automatic vending machine.
Conventional temperature control systems for an automatic vending machine for cooling commercial articles or substances to a predetermined temperature and discharging them on customer demand switch a refrigerant compressor motor ON and OFF in response to detection signals from temperature adjusters disposed in the storage section of the machine. Only a small temperature change triggers the ON-OFF operation due to the performance of the temperature adjusters in such systems, however, and as a result the motor compressor is frequently started and stopped which increases the electric power loss.
Further, in conventional control systems, the motor compressor is also switched ON and OFF during the night when the commercial articles are not vended, which results in unnecessary cooling and attendant electric power consumption.
Furthermore, the vending machine is often connected to a commercial power source by a receptacle which may become unplugged inadvertently and thereby render the power source voltage unstable. If the power source is restored after interruption, or when the commercial articles are restocked it is necessary to adequately cool or heat the articles to a predetermined temperature.